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Comment on Honda successfully launched and landed its own reusable rocket

In different ways. For example, it’s very rare for a car to explode in a collision, other than in movies.

One of the reasons that make hydrogen difficult to work with in this sense is that hydrogen (H₂) molecules are so small that they can permeate most materials, such as steel. Then it can get somewhat easily to wherever there is a spark, and chaos ensues. Annoyingly you don’t even need 100% Hydrogen for that to happen, as it can ignite with a concentration of just 4%.

After we stopped using Hydrogen mostly as a consequence of Hindenburg’s accident, it’s taken years to perfect hydrogen fuel cells to a safety standard that can be used in cars. As far as I know, its use has been limited to rockets/space propulsion otherwise (where you can just throw millions at the problem to make it safer).

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xavier666@lemm.ee ⁨1⁩ ⁨day⁩ ago

(H₂) molecules are so small that they can permeate most materials, such as steel

Okay, I knew from texts books that H2 is small but I never thought of the real-life consequences of it being so small. Then theoretically, Helium should also be “leaky”, right?

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- MysteriousSophon21@lemmy.world ⁨1⁩ ⁨day⁩ ago
  Yep, helium is even worse for leaking! It’s actually the smallest noble gas and can escape through tiny pores that even hydrogen can’t fit through. Thats why helium balloons deflate faster than air balloons - the atoms literally seep through the balloon material.
  
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  - stephen01king@lemmy.zip ⁨1⁩ ⁨day⁩ ago
    How does Helium fit through places that Hydrogen can’t even though its bigger? Is it because Hydrogen would react with things along the way while Helium won’t?
    
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    gandalf_der_12te@discuss.tchncs.de ⁨1⁩ ⁨day⁩ ago
    I suspect it’s because the hydrogen molecules are bigger than a single helium atom, which doesn’t form molecules (since it’s a noble gas).
    
    So the hydrogen molecule only seeps through if it’s oriented right (since the hydrogen molecule is a stick-shaped molecule).
    
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    Cocodapuf@lemmy.world ⁨1⁩ ⁨day⁩ ago
    I’m also curious, I thought hydrogen was the worst in this regard.
    
    I like your theory on hydrogen reacting as it moves through materials.
    
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